Gold Knoll Collection System Upgrade at Royal Mountain King Mine

Gold Knoll Collection System Upgrade at Royal Mountain King Mine

The Gold Knoll-Royal Mountain King Project is part of the Regional Water Quality Control Board Order 5-01-040 and Waste Water Discharge Requirements R5-2008-0021 to control discharges from the Royal Mountain King Mine Site in Calaveras County. The project proposes to upgrade the Gold Knoll collection System by replacing the existing open pond system with buried sump, collection trench, and blanket drain to provide for collection of captured flows to the maximum extent possible. The captured flow from the Gold Knoll Overburden Disposal System (ODS) will be pumped to Skyrocket Pit Lake where the stored water will be released to Littlejohn's Creek under NPDES Permit CA0085243. The proposed design incorporates a linear collection trench that follows a contour along the northeast, north, and northwest sides of upper pond. On the east side of the upper pond a 20 foot wide blanket drain will be extended upland of the collection trench to collect seeps that emerge above the pond level. A 12 foot deep collection sump will be constructed at the uppermost corner of the existing pond. All excavated areas will be lined with geo-textile material, backfield with gravel, capped with 2 feet of soil/clay cover, and revegetated. The area surrounding the sump will be backfilled with 5 feet of soil to allow the surface water runoff to pass over the top of the sump without ponding or infiltrating. The fill will extend approximately 20 feet to the south of the sump and its surface will drain to the east. A 400 gpm capacity submersible sump pump and float activated level switches will be installed in the sump and connected to aboveground pipe conveying captured flows to Skyrocket Pit Lake.

Calaveras